This invention is related to U.S. Pat. application commonly owned Ser. No. 07/895,334, entitled "Method And Apparatus For Opening Folded Printed Products And Depositing Them On A Saddle-Type Rest" filed concurrently herewith.
The present invention relates to a method and an apparatus for processing printed products, such as newspapers, magazines or parts thereof and particularly to a method and apparatus for conveying printed products with controllable grippers of a conveying device.
A method and apparatus of this type are disclosed, for example, in EP-A-0,208,081 and the corresponding U.S. Pat. No. 4,684,116 and U.S. Pat. No. 4,684,117. In the arrangement disclosed in these references, the printed products are folded asymmetrically or off-centered. The folded printed products are then held or gripped at the fold by individually controllable conveying grippers of a conveying device and are transported, with the leading edge region which is open and opposite the fold. The printed products are transported in a conveying direction which runs obliquely in a downward direction. Positioned below the conveying device is an opening device with controllable opening grippers which are arranged on two mutually parallel circulating traction or drawing members. In order to bring the edge region of the printed products into the range of action of the opening gripper, the corresponding conveying gripper is opened briefly. As the conveying gripper is opened, the part of the printed product lying at the bottom slides into the mouth of the corresponding opening gripper. Further downstream, the traction member is deflected around a deflecting wheel. The deflecting wheel is arranged such that the deflection of the traction member is transverse to the conveying direction. As the traction member is deflected, the part of the product now held on the edge region by the opening gripper is moved away or separated from the non-held part of the product lying at the top. A collecting conveyor is introduced from below between the partially separated parts of the product. When the gripper is now opened, the printed product drops astride on the collecting conveyor.
An apparatus for opening folded printed products is disclosed in Swiss Patent Specification 667,859. In the disclosed arrangement, the printed products are held at the fold securely against rotation by the grippers of a conveying device. The printed products are also compressed by means of a pusher element which acts on an end region of the fold. An opening strip is introduced between the halves of the printed products starting from the compressed fold. In order for the strip to separate the two halves from one another from the region of the fold, the strip is moved along the relevant side edge of the printed product to the region of the open side edge opposite the fold. Each of the grippers have two clamping fingers which can be controlled independently of one another and a clamping jaw which interacts with the two clamping fingers. This arrangement holds the gripped printed products securely against rotation. In order to open the printed products completely, the clamping finger which is closest to the pusher element is moved into its open position. The effect of the pusher element on the fold positions the respective printed product obliquely. This allows a circulating opening cam to be introduced in the open edges of one-half of the printed product to hold that one-half of the printed product. The half of the printed product which is held by the opening cam is then deflected to separate it from the other half in some areas. A saddle-type rest of a collecting drum can then be inserted between the two halves. The other clamping finger then opens such that the printed product drops astride the saddle-type rest. With this apparatus, however, the printed products cannot be aligned for subsequent processing because the opened printed products become deformed under the effect of the pusher element.
When printed products are transported by means of conveying devices with individually controllable grippers, the position of each printed product relative to the relevant gripper is determined by the positioned of the printed product when it is gripped by the gripper. The printed products, therefore, often have different positions relative to their corresponding grippers. It is desirable and important, however, in some further processing operations of the printed products to have all of the printed products assume a precisely defined position.
Therefore, a primary object of the present invention is to provide a method and apparatus which precisely positions printed product relative to controllable grippers which transport the printed products.